// SPDX-License-Identifier: MIT
/*
Copyright 2007, 2008 by Grégoire Henry, Julien Cristau and Juliusz Chroboczek
Copyright 2011, 2012 by Matthieu Boutier and Juliusz Chroboczek
*/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <sys/time.h>
#include <sys/param.h>
#include <time.h>
#include <fcntl.h>

#include "babeld.h"


#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>

#include <zebra.h>
#include "prefix.h"
#include "zclient.h"
#include "kernel.h"
#include "privs.h"
#include "command.h"
#include "vty.h"
#include "memory.h"
#include "frrevent.h"
#include "nexthop.h"

#include "util.h"
#include "babel_interface.h"
#include "babel_zebra.h"


static int zebra_route(int add, int familt, const unsigned char *pref, unsigned short plen,
		       const unsigned char *gate, int ifindex, unsigned int metric);

int kernel_interface_operational(struct interface *interface)
{
	return if_is_operative(interface);
}

int kernel_interface_mtu(struct interface *interface)
{
	return MIN(interface->mtu, interface->mtu6);
}

int kernel_interface_wireless(struct interface *interface)
{
	return 0;
}

int kernel_route(enum babel_kernel_routes operation, const unsigned char *pref,
		 unsigned short plen, const unsigned char *gate, int ifindex, unsigned int metric,
		 const unsigned char *newgate, int newifindex, unsigned int newmetric)
{
	int rc;
	int family;

	/* Check that the protocol family is consistent. */
	if (plen >= 96 && v4mapped(pref)) {
		if (!v4mapped(gate)) {
			errno = EINVAL;
			return -1;
		}
		family = AF_INET;
	} else {
		if (v4mapped(gate)) {
			errno = EINVAL;
			return -1;
		}
		family = AF_INET6;
	}

	switch (operation) {
	case ROUTE_ADD:
		return zebra_route(1, family, pref, plen, gate, ifindex, metric);
	case ROUTE_FLUSH:
		return zebra_route(0, family, pref, plen, gate, ifindex, metric);
	case ROUTE_MODIFY:
		if (newmetric == metric && memcmp(newgate, gate, 16) == 0 && newifindex == ifindex)
			return 0;

		rc = zebra_route(1, family, pref, plen, newgate, newifindex, newmetric);
		return rc;
	}

	return 0;
}

static int zebra_route(int add, int family, const unsigned char *pref, unsigned short plen,
		       const unsigned char *gate, int ifindex, unsigned int metric)
{
	struct zapi_route api;		/* quagga's communication system */
	struct prefix quagga_prefix;	/* quagga's prefix */
	union g_addr babel_prefix_addr; /* babeld's prefix addr */
	struct zapi_nexthop *api_nh;	/* next router to go - no ECMP */

	api_nh = &api.nexthops[0];

	/* convert to be understandable by quagga */
	/* convert given addresses */
	switch (family) {
	case AF_INET:
		uchar_to_inaddr(&babel_prefix_addr.ipv4, pref);
		break;
	case AF_INET6:
		uchar_to_in6addr(&babel_prefix_addr.ipv6, pref);
		break;
	}

	/* make prefix structure */
	memset(&quagga_prefix, 0, sizeof(quagga_prefix));
	quagga_prefix.family = family;
	switch (family) {
	case AF_INET:
		IPV4_ADDR_COPY(&quagga_prefix.u.prefix4, &babel_prefix_addr.ipv4);
		/* our plen is for v4mapped's addr */
		quagga_prefix.prefixlen = plen - 96;
		break;
	case AF_INET6:
		IPV6_ADDR_COPY(&quagga_prefix.u.prefix6, &babel_prefix_addr.ipv6);
		quagga_prefix.prefixlen = plen;
		break;
	}
	apply_mask(&quagga_prefix);

	memset(&api, 0, sizeof(api));
	api.type = ZEBRA_ROUTE_BABEL;
	api.safi = SAFI_UNICAST;
	api.vrf_id = VRF_DEFAULT;
	api.prefix = quagga_prefix;

	if (metric >= KERNEL_INFINITY) {
		zapi_route_set_blackhole(&api, BLACKHOLE_REJECT);
	} else {
		SET_FLAG(api.message, ZAPI_MESSAGE_NEXTHOP);
		api.nexthop_num = 1;
		api_nh->ifindex = ifindex;
		api_nh->vrf_id = VRF_DEFAULT;
		switch (family) {
		case AF_INET:
			uchar_to_inaddr(&api_nh->gate.ipv4, gate);
			if (IPV4_ADDR_SAME(&api_nh->gate.ipv4, &quagga_prefix.u.prefix4) &&
			    quagga_prefix.prefixlen == IPV4_MAX_BITLEN) {
				api_nh->type = NEXTHOP_TYPE_IFINDEX;
			} else {
				api_nh->type = NEXTHOP_TYPE_IPV4_IFINDEX;
			}
			break;
		case AF_INET6:
			uchar_to_in6addr(&api_nh->gate.ipv6, gate);
			/* difference to IPv4: always leave the linklocal as nexthop */
			api_nh->type = NEXTHOP_TYPE_IPV6_IFINDEX;
			break;
		}
		SET_FLAG(api.message, ZAPI_MESSAGE_METRIC);
		api.metric = metric;
	}

	debugf(BABEL_DEBUG_ROUTE, "%s route (%s) to zebra", add ? "adding" : "removing",
	       (family == AF_INET) ? "ipv4" : "ipv6");
	return zclient_route_send(add ? ZEBRA_ROUTE_ADD : ZEBRA_ROUTE_DELETE, babel_zclient, &api);
}

int if_eui64(int ifindex, unsigned char *eui)
{
	struct interface *ifp = if_lookup_by_index(ifindex, VRF_DEFAULT);
	if (ifp == NULL) {
		return -1;
	}

	uint8_t len = (uint8_t)ifp->hw_addr_len;
	char *tmp = (void *)ifp->hw_addr;

	if (len == 8) {
		memcpy(eui, tmp, 8);
		eui[0] ^= 2;
	} else if (len == 6) {
		memcpy(eui, tmp, 3);
		eui[3] = 0xFF;
		eui[4] = 0xFE;
		memcpy(eui + 5, tmp + 3, 3);
	} else {
		return -1;
	}
	return 0;
}

/* Like gettimeofday, but returns monotonic time.  If POSIX clocks are not
   available, falls back to gettimeofday but enforces monotonicity. */
void gettime(struct timeval *tv)
{
	monotime(tv);
}

/* If /dev/urandom doesn't exist, this will fail with ENOENT, which the
   caller will deal with gracefully. */

int read_random_bytes(void *buf, size_t len)
{
	int fd;
	int rc;

	fd = open("/dev/urandom", O_RDONLY);
	if (fd < 0) {
		rc = -1;
	} else {
		rc = read(fd, buf, len);
		if (rc < 0 || (unsigned)rc < len)
			rc = -1;
		close(fd);
	}
	return rc;
}
